1. Field of the Invention
The present invention relates generally to construction equipment such as backhoes and, more particularly, to a movable thumb or closure element, which operates in conjunction with a hydraulically controlled bucket. While the present invention is described in terms of a backhoe bucket, the present invention may be utilized with other construction equipment having a pivotally mounted bucket for operation on a hydraulic arm.
2. Description of the Prior Art
Most backhoes are equipped with a hydraulically pivotal bucket. If only the backhoe bucket is used, it is very difficult to pick up objects such as a tree because if the object or tree is not perfectly balanced on the bucket, then the object or tree will tend to fall off. As well, it may be difficult to grasp objects such as trees for lifting or pulling purposes.
Because of this problem, a fixed thumb or hydraulic control thumb may be attached for use with a bucket. As used herein a thumb is a closure element of some type against which the bucket may be rotated for grasping purposes. A movable thumb in accord with the present invention is discussed hereinafter.
The disadvantage of a fixed thumb or closure element is that the fixed thumb must be pushed against the object, such as a tree by lowering the lifting boom and moving the stick boom of the backhoe toward the object. Then the bucket is rotated against the thumb. Another problem with a fixed thumb is that the fixed thumb may interfere with other operations of the bucket. The fixed thumb does not permit wide range of different size objects to be manipulated. The fixed sum is also not in the right position to be of any use to pick up a pile of loose dirt or other material.
The prior art hydraulically operated movable thumb requires the movable thumb to be moved toward the object, whereupon the bucket is rotated against the thumb. This action requires the operator's use of multiple levers, which is slow and over time becomes tedious. The operation may also be complex. The hydraulically operated thumb and bucket operation may require the operator to use three levers simultaneously for grasping and lifting. The limited range of movement of the hydraulically operated thumb limits the variation in size of the objects, such as trees or poles, which can be manipulated by the backhoe.
The above cited prior art does not disclose a movable thumb that permits the operator to use a single lever to control pivotal motion of the backhoe bucket and the movable thumb simultaneously. The solutions to the above described and/or related problems have been long sought without success. Consequently, those skilled in the art will appreciate the present invention that addresses the above and other problems.